1. Technical Field
Embodiments exemplarily described herein relate generally to semiconductor memory devices and more particularly to resistive memory elements.
2. Description of the Related Art
Recently, techniques of forming memory devices that use a material having a resistance that is reversibly switchable between two resistive states have been proposed. Colossal magneto-resistance (CMR) material is known to be switchable between low and high resistive states in response to a voltage pulse applied thereto. For example, if a positive voltage pulse is applied to CMR material exhibiting a high resistive state, the CMR material responds by exhibiting a low resistive state. If a negative voltage pulse is applied to the CMR material exhibiting a low resistive state, the CMR material responds by exhibiting a high resistive state. When many voltage pulses of one polarity are applied to the CMR material, the CMR material responds by gradually changing resistive states and gradually returns to its original resistive state when voltage pulses of an opposite polarity are applied thereto. Based upon these response characteristics described above, CMR material poses many challenges that must be overcome to form an advanced multi-bit memory device capable of storing more two bits in a single memory cell.